Downloader

import * as path from "path";
import * as fs from "fs";
import { URL } from "url";
import * as http from "http";
import * as https from "https";

class Downloader {

public downloadFile(downloaderUrl: URL): void {
    if (downloaderUrl.protocol === "http:") {
        this.httpDownload(downloaderUrl);
    } else if (downloaderUrl.protocol === "https:") {
        this.httpsDownload(downloaderUrl);
    } else {
        console.error(`Downloader is not support ${downloaderUrl.protocol.split(":")[0]} protocol!`);
    }
}

private httpDownload(downloaderUrl: URL): void {
    
    let error: Error | null | undefined;

    http.get(downloaderUrl, (res) => {
        if (res.statusCode === 200) {
            let writer = fs.createWriteStream(path.join(__dirname,"http"),"UTF-8");
            res.pipe(writer);
            writer.on('finnish',()=>{
                res.unpipe();
                writer.close;
            });
        } else if (res.statusCode == 302) {
            let location = res.headers['location'];
            console.log(location);
            if(!(location===undefined)){
                this.downloadFile(new URL(location));
            }
        } else {
            error = new Error('Request Failed. ' + `Status Code: ${res.statusCode}`);
        }
        if (!(error === null || error === undefined)) {
            console.error(error.message);
            res.resume();
            return;
        }
    });
}

private httpsDownload(downloaderUrl: URL): void {

    let error: Error | null | undefined;
    
    https.get(downloaderUrl, (res) => {
        if (res.statusCode === 200) {
            let writer = fs.createWriteStream(path.join(__dirname,"a.html"),"UTF-8");
            res.pipe(writer);
            writer.on('finnish',()=>{
                res.unpipe();
                writer.close;
            });
        } else if (res.statusCode == 302) {
            let location = res.headers['location'];
            console.log(location);
            if(!(location===undefined)){
                this.downloadFile(new URL(location));
            }
        } else {
            error = new Error('Request Failed. ' + `Status Code: ${res.statusCode}`);
        }
        if (!(error === null || error === undefined)) {
            console.error(error.message);
            res.resume();
            return;
        }
    });
}

}

let httpUrl: URL = new URL("http://url.12306.com/aXANGN")
let html:URL = new URL("https://www.baidu.com/");
let httpsUrl: URL = new URL("https://github.com/gohugoio/hugo/releases/download/v0.52/hugo_extended_0.52_macOS-64bit.tar.gz");
let ftpUrl: URL = new URL("ftp://ftp.freebsd.org/pub/FreeBSD/README.TXT");

let down: Downloader = new Downloader();

//down.downloadFile(httpUrl);
//down.downloadFile(html);
//down.downloadFile(httpsUrl);
//down.downloadFile(ftpUrl);